SAT MATH: ADDITIONAL TOPIC IN MATH

In SAT only 6 of the 58 questions come from this section and this is the most challenging section of SAT. Thus I would recommend you to study this part after you have gained confidence in all other sections.

In other sections there were some topics missing like Geometry, Trigonometry etc. Those remaining parts are discussed in this section. With the help of this section you will be able to see the beauty of nature like never before, if you keep your mind open. Geometry and trigonometry act as base for all architectural creations whether natural or man made.




GEOMETRY

In this part we will be discussing about geometry and mainly focusing on lines, circles and triangles.

LINE - The shortest distance between 2 points. It has no ends whereas a line segment has 2 fixed ends.
A ray has 1 fixed end and 1 extending to infinity.




Let there be a line AB and C be it's midpoint then it means that 
AC = BC and the segment is divided into 2 equal parts.


ANGLE 

The space between 2 intersecting lines is called as angle. It's a figure formed by 2 rays. 

There are 5 types of angles.

ACUTE ANGLE → Less Than 90 Degree

RIGHT ANGLE → Equal To 90 Degree

OBTUSE ANGLE → Between 90 Degree And 180 Degree

STRAIGHT LINE → Equal To 180 Degree

REFLEX ANGLE → Between 180 Degree and 360 Degree


If there is an angle at vertex A formed by Rays AB and AC then it will be denoted as ∠BAC.

COMPLIMENTARY ANGLES - If 2 angles add up to 90 degrees then they are known as complimentary angle.

SUPPLEMENTARY ANGLES - If 2 angles add up to 180 degrees them they are known as Supplementary angle.

PARALLEL LINES

Two lines who never meet each other are called to be parallel lines. If you place 1 line over another you will find that they have angle of 0 degree between them.

Let's discuss about angles formed when 2 parallel lines are intersected by 1 another.



A) VERTICAL ANGLES - Angles with common vertex but different side of lines. Here angle 1 & 3, 2 & 4, 5 & 7 and 6 & 8 are vertical angles.

All the vertical angles are equal.

angle 1 = 3, 2 = 4, 5 = 7, 6 = 8

B) ALTERNATE INTERIOR ANGLES - They generally make a Z. They are interior angles present on opposite sides of the line intersecting the parallel lines. like angle 3 & 5, 4 & 6.

Alternate interior angles are equal

Angle 3 = 5 and 4 = 6

C) ALTERNATE EXTERIOR ANGLE - Just like alternate interior angles with the difference that in it there are exterior angles instead of interior angles.

Alternate exterior angles are equal

Angle 1 = 7 and 2 = 8

D) CORRESPONDING ANGLES - In it the angles are present at similar position. EX - angle 1 & 5, 2 & 6, 3 & 7 and 4 & 8.

Corresponding angles are equal

Angle 1 = 5, 2 = 6, 3 = 7, 4 = 8


# EQUATION OF LINE


you can find the equation of a line if slope and a point is given.
Let slope = m, point = (X1,Y1)

m = (Y – Y1)/(X – X1)

You see the slope = ΔY/ΔX 
We will be using this formula when 2 points like (X1,Y1) and (X2,Y2) are given.

slope = (Y – Y1)/(X – X1)
= (Y2 – Y1)/(X2 – X1)


CIRCLE

A circle is a figure equidistant from 1 point, with that 1 point referred as it's center.

Area of circle = πR2
circumference(perimeter) = 2πR

Here this values is for the complete circle if you want to find the values for a sector that is a section of a circle 
then multiply it by θ/2π, where θ is the angle subtended by arc on the center.

So for a sector subtending angle θ at center.

Area of circle = πR2×θ/2π = R2θ/2

Circumference = 2πR × θ/2π = Rθ

The total angle a point can subtend is 360 degree. like here it is 
180 degree + 180 degree .



The conversion of Radian and degree is

180 degree = π

360 degree = 

So when we multiply it by θ/2π we are actually multiplying this to get the share of that sector.

EQUATION OF CIRCLE

for a circle with center (X1,Y1) and radius r.


(X  - X1)2 + (Y – Y1)2 = R2

Your goal is to convert all the forms of equation of circle into this.

THEOREMS OF CIRCLE

1) Angle at the center is twice the angle at circumference.
2) Angle in semicircle is  a right angle.
3) Angles in same segments are equal.
4) opposite angles in a cyclic quadrilateral sum up to 180 degree. Here, cyclic quadrilateral is a quadrilateral whose all 4 vertices lie on the circumference of a circle.


# TANGENTS AND NORMAL

Tangent - A line touching the circle at only 1 point. It's perpendicular to the radius.

Normal - The line joining the center of a circle to tangent is called as normal.

#CHORDS


The line joining any 2 segment of circle is called a chord. Diameter is a special chord which passes through center. It's the longest chord.

TRIANGLES

In this section we will be discussing about the various properties of triangles. We already know that a triangle is a figure of 3 sides and 3 angles.

Let's start with the Pythagorean theorem.

In right triangle where one of an angle is 90 degree

Hypotenuse = Side2 

C2 = A2 + B2

It will be very handy in questions asking length of a side with questions combining circles and triangles.

EQUILATERAL TRIANGLE - In these all the 3 sides are of equal length and all the angles are equal to 60 degrees.

ISOSCELES TRIANGLE - In these 2 sides are equal and their opposite angles are equal.

CONGRUENCE

Two figures are said to be congruent when they can be imposed over one another i.e. they are the exact copy of one another.

There are certain conditions for 2 triangles to be congruent i.e.

1)SSS (Side Side Side) - All sides of both triangles are equal.

2) SAS (Side Angle Side) - 2 Sides and angle between them is equal.

3) AAS (Angle Angle Side) - 2 Angles and side are equal

4) HL (Hypotenuse Leg) - For 2 right angled triangles their Hypotenuse and one side is equal.

SIMILARITY

Two figures are said to be similar if their shape is same but their size may differ.

Condition to find if 2 triangles are similar.

1) SSS(Side Side Side) - If all the corresponding sides are proportional.

2)SAS(Side Angle Side) - If 2 sides are proportional and angle between them is same.

3) AA(Angle Angle) - If 2 of the angles are equal.

If ΔABC is similar to ΔDEF

then, ∠A = ∠D,∠B = ∠E and ∠C = ∠F

AB/DE = BC/EF = AC/DF

TRIANGLE INEQUALITY THEOREM - Sum of the lengths of any 2 sides is greater than the length of third side.

REGULAR POLYGON - Any polygon with all sides equal in length is called as Regular Polygon.

SQUARE - A quadrilateral with all 4 sides equal and both diagonals equal. All 4 angles = 90 degrees

Perimeter = 4 × side
Area = side2


RECTANGLE - A quadrilateral with opposite sides equal and with both diagonals equal. All 4 angles = 90 degrees.

Perimeter = 2( length + breadth)
Area = length × breadth


PARALLELOGRAM - A quadrilateral with opposite sides equal and parallel. Diagonals bisect each other.

Perimeter = 2( length + breadth)
Area = length × breadth


TRAPEZIUM - A quadrilateral in which 1 pair of sides are parallel and remaining are not.

Perimeter = Sum of 4 sides
Area = height × (sum of parallel sides)/2


AREA AND VOLUME

In SAT, area and volume formulas are given in the question paper so you don't have to memorize it. You just need to apply them.



TRIGONOMETRY

In a right angled triangle ABC Let ∠A be θ
sinθ = opposite side/hypotenuse
cosθ = adjacent side/hypotenuse
tanθ = opposite side/adjacent side

it's also referred as Soh Cah Toa in short. You can remember it in this way.

cotθ = adjacent side/opposite side
secθ = hypotenuse/adjacent side
cosecθ = hypotenuse/opposite side

PROPERTIES

sin(90-θ) = cosecθ
cos(90-θ) = secθ
tan(90-θ) = cotθ
cot(90-θ) = tanθ
sec(90-θ) = cosθ 
cosec(90-θ) = sinθ 



sinθ = 1/cosecθ
cosθ = 1/secθ

tanθ = 1/cotθ
cotθ = 1/tanθ
secθ = 1/cosθ

cosecθ = 1/ sinθ



Sin2θ + cos2θ = 1
Sec2θ = 1 + tan2θ

Cosec2θ =  1 + cot2θ

These identities and properties are very handy while solving SAT questions.


Now come the less important ones

sin(a+b) = sin(a)cos(b) + cos(a)sin(b)
sin(a-b) = sin(a)cos(b) - cos(a)sin(b)
cos(a+b) = cos(a)cos(b) – sin(a)sin(b)
cos(a-b) = cos(a)cos(b) + sin(a)sin(b)


COMPLEX NUMBERS

Till now all the numbers we have studies were real numbers. Now come the complex or imaginary numbers. They contain an  iota referred as 'i'.

Z(Complex number) = a +bi     where i = √(-1)


conjugate of Z  = a - bi
the property of conjugate is that in it, the imaginary part get's it's sign changed.


Now coming to iota as you can see 
i2 = -1

and i4 = 1


thus if you want to calculate i127 remove i124 as it's multiple of ithus equal to 1 and calculate

i3 = -1 ×i = -i








                                                                        BONNE CHANCE !




SAT HOMEPAGE
SAT EXAM FORMAT
SAT READING
SAT WRITING
SAT MATH
SAT MATH: HEART OF ALGEBRA
SAT MATH: PROBLEM SOLVING AND DATA ANALYSIS
SAT MATH: ADDITIONAL TOPIC IN MATH
SAT MATH: PASSPORT TO ADVANCE MATH
SAT MATH:GRAPH
SAT ESSAY



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